The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: spyke on 20.05. 2011 19:12
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Finally traced a strange feeling of riding what felt like a horse ie a lollopyand undulating (not vibration) to the rear wheel, by running the bike in 4th gear whilst jacked up in the air.Thought thats good, now i know what it is, and took the wheel to have it dynamically balanced, but when her indoors went to collect it for me they said it would have taken so many weights (130g i think she said) that it would have been too asthetically unpleasing (tyre blokes words) so he wouldnt do it.
Ive spun it up with the spindle clamped in the vice and it doesnt look that bad to me ie.about 1/2 mm run out eccentrically and same side to side.
My question is would it be worth giving it to a wheel right to let him try and true it more or or have i got to say goodbye to another 200 squid and have a new rim etc.? What else can make it SO out of balance , i dont think ive ever had to have a motorcycle wheel balanced ever before.
The wheel is a chromed steel dunlop rim ,18" dia with one security bolt about a third of way round from valve, fitted with 4" trials tyre, which has an even gap round the perimeter line.
Cheers Spyke
PS the wheel was not new or rebuilt when i fitted it .
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Think your allowed 1mm run out so truing it any more is not necessary
Do you need a security bolt?
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I thought you needed one on a back wheel, it had a holes for two in the rim?
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G'day Spyke,
1/2mm is fine, do you need a rim lock? Have you tried re-positioning the tyre 180 degrees?
Cheers
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I dont know if i need a sec bolt, although ive got a trials tyre i will never run it low pressure as a trials bike would.
Is it safe to get rid of it and did bsa fit originally?
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I would get rid of it, I don't have any on any of my bikes.
The idea of them is to prevent tyre creep and ripping out the valve. I cant see how they can be successful though.
To prevent the tyre from creeping on the rim you must use a suitable lubricant/soap when fitting the tyre, notice how when you come to remove a tyre from the rim it is often stuck, sometimes even stuck with rust on the rim if it has not been off for a long time, this is what you want as it does a far better job than the clamp,lock or whatever.
I've used a little washing up liquid when fitting the tyre, wiping away remains with a clean rag when done. It also pays to leave the valve nut off so that you can see if the valve remains vertical to the rim as it should, if after some heavy braking the valve appears at an angle then you'll know the tyre has slipped around the rim. Hope this helps towards solving the unbalanced tyre problem.
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I agree with LJ, don't have a security bolt on any of my bikes...
Try another tyre, maybe see if you can borrow one from somewhere as that would be the first thing I'd suspect..
Adrian.
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Would be interesting to see how the balance is without the tyre on. Had a look at the cafe, 85g front 75g rear, but that was static balance.
Cheers